The present invention relates to toy building sets and in particular to a shock absorber for toy building sets, said shock absorber comprising a substantially rod-shaped element having at its one end a collar and a guide comprising a sleeve which displaceably encloses the rod-shaped element; and wherein the rod-shaped element and the guide each has means for mounting on another construction; and wherein a spring is arranged which, with its one end, abuts on the rod-shaped element and, with its other end, abuts on the sleeve in such a manner that it uses its spring force to displace the above-mentioned sleeve towards the collar on the first mounting element.
Such shock absorbers are often used in toy building sets for the construction of mechanical models, such as vehicles and the like, wherein the shock absorber can be arranged on movable elements of some kind of movable construction in such a manner that a springy movement is obtained. When the shock absorber is used, e.g., in the construction of a vehicle, the shock absorber can serve as a shock absorber for the movable wheel suspension of the vehicle whereby the model thus built will act approximately as a real vehicle.
U.S. Pat. No. 5,056,764 teaches, e.g., a shock absorber arranged in such a manner that it can easily be mounted on another construction in that the guide for the rod-shaped element in combination with the collar on the rod-shaped element make it easy to mount the shock absorber on another construction by shifting a slotted portion of the other construction in between the guide and the collar on the shock absorber.
However, it is a problem with this solution that, although adequate spring function can be obtained, only a limited shock absorption is obtained, since the absorbing effect is generated as a result of the friction between the rod-shaped element and the guide, and this friction has to be limited in such a manner that it is ensured that the shock absorber does not by itself, during use, become unstuck from the other construction on which it is mounted.
U.S. Pat. No. 4,869,704 teaches another configuration of a spring device for a toy building set whereby a substantially increased absorption effect is obtained in addition to the spring function in that a conical helical by itself triggers the springy as well as the shock absorbing effect, the individual coils of the conical helical spring being in frictional abutment on each other.
The shock absorbing and springy conical helical spring according to U.S. Pat. Nos. 5,056,764 and 4,869,704, respectively, are arranged in such a manner that the shock absorption and the spring effect are obtained simultaneously.
Moreover, e.g., U.S. Pat. Nos. 3,603,575 and 4,869,704 feature a plurality of embodiments of shock absorbers and shock absorbing elements, the construction of which being unsuitably for use in toys since they are, firstly, configured with a view to use of a hydraulic fluid to obtain the internal shock absorbing friction, and, secondly, their construction is relatively complex.
In light of this, it is the object of the present invention to provide a shock absorber for a toy building set of the type described in the introductory part whereby it is possible, on the one hand, by simple means to obtain a substantially increased shock absorbing effect.
According to the present invention, this is obtained with a shock absorber of the kind described in the introductory part in that the guide further comprises a substantially air-filled cylinder element with a substantially cylindrical inner wall which is so configured that the collar on the rod-shaped element is arranged in displaceable abutment on the inside of the cylinder element.
In an advantageous embodiment of the invention, the collar is configured as a piston, and the piston in elastic abutment on the inner wall of the air-filled cylinder element. Hereby a friction between the piston and the air-filled cylinder element is obtained which yields an adequate absorbing effect.
According to a further preferred embodiment, the means for mounting the rod-shaped part and the guide on another construction comprise respective eyes arranged on each of these whereby it is possible to mount in each of said eyes a shaft end or the like part on another construction.
The cylindrical inner wall on the air-filled cylinder element is particularly advantageously closed at its one end and open at its opposite end. Viz, hereby a shock absorbing effect is obtained when the collar is forcibly shifted in the air-filled cylinder element.
Particularly advantageously, the air-filled cylinder element has, at its open end, means for releasable coupling of the air-filled cylinder element and the sleeve. Viz, it is hereby obtained that the cylinder element and the sleeve with the displaceable rod-shaped element can readily be removed from each other.
According to an alternative preferred embodiment, the air-filled cylinder element and the sleeve are provided with means for snaplocking the sleeve to the air-filled cylinder element which means that the two elements cannot be pulled apart during normal use.
Further advantageously, that end of the rod-shaped element opposite the end where the collar is situated comprises a seat for receiving the one end of the spring, and where the other end of the spring abuts on a second seat arranged on the sleeve. Hereby the sleeve with the displaceable rod-shaped element and the spring can be removed from the cylinder element as an integral unit without the spring being dismounted.
In this context, the spring is particularly advantageously a helical spring which is so arranged as to substantially enclose the rod-shaped element.
The above-described separation of the shock absorber is further facilitated by a particularly advantageous embodiment of the invention wherein the means for releasably mounting the air-filled cylinder element on the sleeve is constituted by an abutment surface located at the open end on the air-filled cylinder element and a complementarily configured abutment surface located on said sleeve, and positioning means configured with a view to preventing sideways displacement of the air-filled cylinder element relative to the sleeve. Viz, it is hereby obtained that the cylinder element can be separated from the remaining part of the shock absorber simply by pulling the two elements apart.
Such authentic embodiment of the shock absorber is obtained provided the means for mounting of the rod-shaped element on another construction are arranged on the end of the rod-shaped element which is opposite that end on which the collar is arranged.
In this context, the sleeve is particularly advantageously provided with a through-going opening through which the rod-shaped element can be shifted; and in that the opening has an internal cross sectional dimension that exceeds the cross sectional dimension of the rod-shaped element, measured in the same direction, whereby the rod-shaped element can be shifted substantially without friction in the through-going opening in the sleeve.
Further advantageously, the means for releasable mounting of the guide on another construction are arranged on the cylinder element; and in that the cylinder element has a cylindrical inner wall which is air-tightly closed at the one end, and at the opposite end has an abutment surface for abutment on a corresponding abutment surface configured on the sleeve, whereby the cylinder element and the guide together from a cylindrical space in which the collar can be shifted, and wherein that end of the cylindrical space where the guide is arranged features ventilation passages with a view to ensuring a substantially unimpeded flow of air from the cylindrical space.
According to a preferred embodiment, the piston is configured as a disc in a rubber-elastic material, and said disc has a centrally arranged through-going opening, and the rod-shaped element has an annular recess at its one end, and wherein the disc is mounted on the rod-shaped element in that the annular recess extends through the central opening in the disc. Hereby it is obtained that it is extremely simple to mount that part of the shock absorber that comprises the rod-shaped element, the spring and the sleeve.
A particularly advantageous embodiment is obtained when the annular recess has a given width and when the disc has a thickness which is smaller than the width of the annular recess, whereby the disc is allowed to be displaced in the annular recess longitudinally of the rod-shaped element; and wherein the annular recess is delimited by a first abutment surface that restricts the displacement of the disc in a direction towards the one end of the rod-shaped element, and a second abutment surface that restricts the displacement of the disc in the opposite direction, and wherein each of the two abutment surfaces is provided with a groove that extends from the bottom of the annular recess and to the periphery of the recess on the rod-shaped element. This enables the groove to serve as a throttle passage for the air to be forced past the piston by displacement of the piston in the air-filled cylinder element, and it is hereby ensured by simple measures that an even shock absorbing effect is accomplished, also after a protracted period of use.
If the groove in the first abutment surface has a cross sectional area which is different from the corresponding cross sectional area on the second abutment surface, it is further accomplished that a different throttle area is provided which means that the absorbing effect is different, depending on whether the piston is withdrawn from or inserted into the air-filled cylinder element.
The groove in the first abutment surface can thus advantageously have a cross sectional area which is smaller than the corresponding cross sectional area on the second abutment surface, which means that the absorption peaks when the rod-shaped element with the piston is withdrawn from the air-filled cylinder element whereby the absorption completely or partially equalises the spring force so as to obtain that when a given force is exerted, substantially the same resistance to displacement of the piston in the air-filled cylinder element is accomplished.